Telecommunications apparatus, system, and method with an enhanced signal transfer point

ABSTRACT

The present invention is an apparatus, system, and method for converting point codes in a signal transfer point in a telecommunications signaling system. The STP converts point codes which designate the origination and destination signaling points for the message. The conversion is based on information defined by the messages, such as origination or destination information. The present invention creates a virtual signaling system which can be reconfigured at the STP by converting point codes, and thus, altering the identities of the signaling points. The present invention is also operable to convert circuit identification codes and transfer integrated services user part messages to a user part.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of prior application of Ser.No. 09/946,029, filed on Sep. 4, 2001, which is a continuation of priorapplication Ser. No. 09/116,868, filed on Jul. 16, 1998, which is acontinuation of prior application Ser. No. 08/525,868 filed on Sep. 8,1995, which is a continuation-in-part of prior application Ser. No.08/238,605, entitled “Method, System, and Apparatus forTelecommunications Control”, filed on May 5, 1994, and currently pendingand that is herein incorporated by reference into this application.

BACKGROUND

[0002] 1. Field of the Invention

[0003] The invention relates to telecommunications and specifically toan enhanced signal transfer point (STP) which alters the point codes intelecommunications signaling and supports User Parts in addition toproviding standard STP functionality. The enhanced STP can form aportion of a telecommunications system.

[0004] 2. Description of the Prior Art

[0005] Telecommunications signaling is the transfer of informationwithin and among telecommunications networks for use by the networks.Signaling information is used to operate the telecommunications networksso these networks can transfer other non-signaling information for thenetwork users. A few examples of signaling operations are call set-up,congestion control, and network management, although there are manysignaling operations. One well known telecommunications signaling systemis Signaling System #7 (SS7). At present, SS7 is the primary signalingsystem used by United States telecommunications providers.

[0006] As is known in the art, and as will be discussed below, STPsroute SS7 signaling within the SS7 network and manage the varioussignaling links which comprise the SS7 network. Routing is accomplishedby processing the routing label of the SS7 message by the MessageTransfer Part (MTP) functionality of the signaling point. The MTP iscomprised of three levels. Levels 1 and 2 facilitate the transfer of SS7messages from one point to another over an individual signaling link.Level 3 facilitates the transfer of SS7 messages over the SS7 networkbeyond the requirements of individual link transmission. In other words,levels 1 and 2 are concerned with transport over individual linkswhereas level 3 is concerned with transport over the SS7 network ingeneral.

[0007] An STP accomplishes its routing task at level 3 through the useof point codes which identify the various signaling points in thenetwork. The STP level 3 will identify the destination point code in anSS7 message and select the proper signaling link for routing thatmessage. For example, if switch A signals a switch B through an STP, themessage will contain the destination point code for the signaling pointin switch B (and the originating point code for switch A). The STP willaccept this signal off of one signaling link, read the destination pointcode, and place the message on the appropriate link for switch B.

[0008] An STP can also control the signaling network through the use ofmanagement messages generated at level 3. In the above example, if therewere signaling links between switch A and the STP, the STP might signalswitch A with instructions to avoid particular links which werecongested or had failed.

[0009] Telecommunications networks are commonly faced with the problemof re-routing user traffic among switches. Traffic may need to bere-routed from one switch to another switch, from one switch to multipleswitches, from multiple switches to one switch, or from one group ofswitches to a different group of switches. When traffic accessing anetwork is directed to a particular switch, the traffic is described asbeing homed to the switch. Traffic being homed to particular switchesmay need to be re-homed to other switches.

[0010] Re-routing the user traffic encompasses changing the connectionsbetween the switches. Connections between switches may be added anddeleted to create new network architectures. Due to the relationshipbetween signaling and network architecture, any change in architectureneeds to be reflected in the signaling system. A common method for doingthis is to re-program the switches to signal each other in accord withthe new architecture. This a complex and time consuming task. Switchescontain numerous data files which must be re-programmed in accordancewith the new routing scheme.

[0011] One prior art system facilitated the transition of trunks from anold switch to a new switch. The system converted the point codes insignaling messages directed to the old switch in response to a change ina trunk assignment from the old switch to the new switch. The converterwas placed between the switch and the STP so that it only handledsignaling on the signaling link connected to the old switch. It used alook-up table to yield the point codes. Since particular trunks would beconnected to either the new switch or the old switch based on anassignment, a table could be constructed to identify the particulartrunk used on a call and convert point codes based on thistrunk/switch/point code assignment. The prior art suggests placing thisconversion function in an STP, but it does not disclose more on thispoint.

[0012] Although this prior art system may be adequate for the limitedscenario encompassing the transition of individual trunks from an oldswitch to a new switch, it does not address the problem of changingnetwork architectures beyond this limited scenario. The prior art systemis designed to serve two switches which share a single switch load and acommon signaling destination. In other words, the system is limited to asituation in which signaling which has already been routed to the oldswitch is split between the old switch and the new switch during thetransition of loads between the two switches.

[0013] As a result of this limitation, several problems are notaddressed by the prior art system. Since it is based on identifyingindividual trunks for point code conversion, signals that cannot beassociated with a specific trunk would not be able to have their pointcodes converted. The prior art system does not address the problem ofhandling management messages which are generated for the control of thesignaling system. Also, the reliance on individual trunk identificationdoes not adequately address situations in which entire switch loads aremoved between switches, or when multiple switch loads are consolidatedon a single switch. Because all trunks between switches are beingchanged over, individual trunk recognition is unnecessary.

[0014] Importantly, the prior art system does not identify theorigination of the signaling message in order to select a destinationfor the signaling. The prior art system does screen the messages whichoriginate from the new switch so these signals can be converted torepresent the old switch as the source of the signaling. This is done inorder to avoid confusion at the destination, but it does not affect theactual selection of the destination. In the prior art system, thedestination is not chosen based on the origin of the message. The priorart system uses only trunk identification to choose the destination.This is detected using either the dialed number or the CircuitIdentification Code (CIC).

[0015] It is also important to note that the prior art system isdesigned only to convert signaling that has been placed on the signalinglink connected to the old switch. This means the STP has alreadyisolated the signaling messages as directed to the old switch. Thus, thesystem does not see signaling directed to any other switch, and it isnot equipped to process signaling that has not been directed to the oldswitch. As such, an STP incorporating this system would convert thepoint codes only after the STP has performed routing processing anddesignated the signaling as being directed to the old switch. Thus, theSTP of the prior art system would not apply to a conversion function forincoming signals which had yet to be routed and could still be directedto any switch.

[0016] Another prior art system provides a signaling gateway between twosignaling systems, for example, a gateway for the signaling systems ofEurope and the United States. The signaling gateway converts point codesbased on the network identification and the destination point code. Thegateway does not convert point codes based on originating information,such as the signaling link or the originating point code. The gatewayalso converts point codes after the destination point code has been usedfor message routing. Also, since the gateway must interface signaling ofdifferent signaling systems, it necessarily includes more functionalityand cost than a point code converter that does not have gatewayfunctionality.

[0017] The above-referenced application discloses a signaling processor.The signaling processor receives, processes and transmits signaling. Insome instances, the signaling processor will not have a point code tofacilitate the routing of signaling messages. In other instances, thesignaling processor may receive signaling that was actually transmittedto a switch, but needs to be processed by the signaling processorinstead of the switch. The prior art does not address the signalingtransfer needs of these signaling processors.

[0018] Typically, an STP routes signaling among several switches.Present systems do not provide an efficient and workable STP which canconvert signaling in a way that accounts for architectural changesaffecting several of the switches. At present, there is a need for anSTP that can better facilitate architecture changes in atelecommunications network.

SUMMARY

[0019] The present invention is an STP, a system, and a method thatsolves the problems posed by changes in architecture and the needs ofsignaling processors. The STP applies Message Transfer Part (MTP)functions to signaling messages that contain point codes. A first meansapplies the signaling data link function, a second means applies thesignaling link function, and a third means applies the signaling networkfunction. A converting means is added for converting at least some ofthe point codes in the signaling messages into different point codes.

[0020] The converting means can be located between the second means andthe routing function of the third means. Point code conversion may bebased on the point codes originally contained in the messages or onorigination information, such as the particular signaling linksets onwhich the messages are transferred to the STP. MTP level 3 managementmessages are also converted. The converting means could be comprised ofa table which is entered using the point codes or linkset designationsand which yields the converted codes. In addition, CircuitIdentification Codes (CICs) can be converted along with the point codes.

[0021] The present invention is operable to transfer integrated servicesuser part (ISUP) messages to any user parts coupled to the STP. The userparts may include signaling processors.

[0022] A signaling system embodying the invention is comprised ofmultiple signaling points linked to a signal transfer point. The linkscan be direct or through other STPs. The signaling points generate andprocess signaling messages and transfer them to the STP over the links.The signaling messages contain codes that identify origination signalingpoints and destination signaling points for the messages. The STP isenhanced in accord with the present invention and is operable to convertdestination codes for signaling messages directed to a plurality ofsignaling points.

[0023] A method embodying the present invention includes receiving asignaling message into the signal transfer point from an originatingsignaling point. The signaling message contains codes which identify theorigination signaling point and the destination signaling point for themessage. The STP then converts at least a portion of the codes in themessage to different codes before the signaling message has beendesignated by the STP for a particular destination signaling point. TheSTP then transfers the signaling message to a signaling link based onthe converted codes. The conversions can be based on the codes in theinitial message and/or on a particular linkset the signaling message isreceived on.

[0024] In one embodiment, telecommunications traffic is re-routed amongswitches. However, the signaling points in the switches are notreprogrammed and continue to generate and transmit signaling to the STPaccording to the old architecture. The STP converts the point codes inthe messages to identify the switch that actually receives the trafficafter the re-route, and routes message to that switch according to theconverted destination point code.

[0025] Advantageously, the conversion function is located prior to theMTP level 3 route function allowing a single integrated and flexiblesystem. Conversions selecting a destination can be based on the originof the signaling. Management messages are also converted to facilitatecontrol of the signaling system.

[0026] In another embodiment, the point codes in signaling messages areconverted between the point code of a signaling processor and the pointcode of other signaling points. This might occur if signaling is beingrouted to a signaling processor instead of a switch even though thesignaling message identifies the destination point code of the switch.Messages from the signaling processor may need to have the originatingpoint code converted to another point code, i.e. the switch that was toreceive the initial message. In another embodiment, the signalingprocessor could be a user part of the STP and require that selectsignaling messages are routed through the signaling processor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, claims, and drawings where:

[0028]FIG. 1 is a block diagram of a signaling system.

[0029]FIG. 2 is a block diagram of a telecommunications networkincluding a signaling system.

[0030]FIG. 3 is a logical diagram of SS7 functionality.

[0031]FIG. 4 is a logical diagram of a version of the invention.

[0032]FIG. 5 is a logical diagram of a version of the invention.

[0033]FIG. 6 is a logical diagram of a version of the invention.

[0034]FIG. 7 is a block diagram of a version of the invention.

[0035]FIG. 8 is a block diagram of a version of the invention.

DESCRIPTION

[0036] As those skilled in the art are aware, SS7 systems are currentlycomprised of basic components such as, signaling points, signalingtransfer points (STPs), and signaling links. Signaling points processthe signaling information to facilitate network operations. Signalinglinks transfer this signaling information among the various signalingpoints. FIG. 1 is provided to illustrate this basic relationship and itshows a basic signaling system comprised of signaling points 10-15 andsignaling links 20-28. Links 20-28 carry signaling used to operate thenetwork, and the actual lines which carry telecommunications traffic arenot shown.

[0037] A common example of a signaling link is a 56 k/bit data linkcontained in a T1 line. However, these links can take many differentforms such as analog links, satellite links, and 1.5 M/bit data links.Typically, the links are grouped into multiple associations of linkscalled linksets.

[0038] Signaling points process the signaling information transferred bythe signaling links. Often, a signaling point is located within atelecommunications switch. As is known, switches typically include acentral processing unit (CPU), a signaling point, and a switch matrix.The signaling point is connected to the switch CPU and provides the CPUwith data so it can control the switch matrix. Switches communicate witheach other through their signaling points over the signaling links. Inthis way, the various switch matrices can be coordinated by the switchCPUs to establish a connection through a series of switches.

[0039] Signaling points can also be located in Service Control Points(SCPs). As those skilled in the art are aware, SCPs include databasesthat respond to signaling from switches. Typically, the SCP will accepta query from a switch as to how a particular call should be routed. TheSCP will process the signaling and respond to the switch with signalingthat provides routing information.

[0040] STPs can function as a signaling point in addition to thesignaling transfer function. The STP accepts multiple signaling linksfrom numerous signaling points. The STP's primary function is routing;placing incoming signaling on the appropriate outgoing signaling link.Typically, the signaling points in switches and SCPs are linked to STPsand transmit signaling to the STPs for routing to the proper destinationsignaling point in another switch or SCP. STPs also perform managementfunctions for the SS7 network.

[0041] Other types of signaling points are equally applicable to thepresent invention. For example, the above referenced signalingprocessors can function as signaling points. In addition, othersignaling systems, such as C7 signaling, are equally applicable to thepresent invention.

[0042]FIG. 2 further illustrates the basic relationship of FIG. 1 and isan overlay of FIG. 1. FIG. 2 shows switches 30-32, STPs 40-41, signalingprocessor 45, and SCP 50 which each include a signaling point that islinked to signaling points in other network elements. As discussed, thesignaling points in the switches are typically coupled with a switch CPUthat controls the switch matrix.

[0043] The SS7 signal itself is a packet, or message, of informationbits. The functionality which processes SS7 signaling messages isfundamentally divided into two parts: the Message Transfer Part (MTP),and the User Part. The function of the MTP is to provide transport forthe SS7 messages within the signaling system. Those skilled in the artare familiar with functions in the User Part, such as the IntegratedService User Part (ISUP), the Telephone User Part (TUP), the TransactionCapabilities Application Part (TCAP), and the Signaling ConnectionControl Part (SCCP). These functions “use” the MTP to transfer signalingmessages over the signaling links of the SS7 network so that the UserPart may process information required by the switches such as dialednumbers, translation numbers, and circuit status.

[0044] Since STPs serve to route and manage the SS7 network, they do notrequire User Part functionality which pertains to information aboutcalls and connections in the general telecommunications network. STPsare concerned with being able to route SS7 messages within the signalingnetwork to the appropriate signaling points in switches and SCPs. TheSTP employs MTP processing to accomplish this function. In addition, theSTP can employ signaling connection control part (SCCP) logic tofacilitate routing. SCCP allows signaling message routing based onlogical connections. For example, a signaling message requesting adialed number translation can be sent to the STP itself SCCP wouldprovide the STP with the point code for the appropriate database thatcould accommodate the translation.

[0045] MTP functionality is comprised of three levels: signaling datalink (level 1), signaling link (level 2), and signaling network (level3). Level 1 represents the bi-directional signal path comprising twodata channels operating together in opposite directions. Level 1 definesthe physical and electrical characteristics of the signaling link.Typically, this entails 56 k/bit data link operation, however, otherforms of links are equally applicable to the present invention. Level 2operates over level 1 to provide for the transfer of signaling frompoint to point over a single data link. This includes delimiting thesignaling messages with flags, bit stuffing, error detection throughcheck bits, error correction through retransmission and sequenceinformation, signal link failure detection, and signal link recovery.For example, on FIGS. 1 and 2, the first two levels might be used toprovide transport over signaling link 20 at 56 k/bit from signalingpoint 10 in switch 30 to signaling point 11 in STP 40. The first twolevels would also ensure that signaling link 20 is monitored for properperformance. Level 3 defines the transport functions that areindependent of the operation of individual signaling links. For example,from switch 30 to SCP 50 on FIG. 2.

[0046] SS7 functionality is illustrated in FIG. 3 with MTP 61 and UserPart 62. The separation of the MTP and the User Part is shown. The MTPhandles transport of signaling messages within the signaling network andthe User Part facilitates the operation of the network which carriestelecommunications traffic. An example of a user part would be asignaling processor. Signaling Data Link 71 (Level 1) which handles thephysical/electrical transport on individual links is coupled withSignaling Link 72 (level 2) which performs monitoring and control ofthese same individual links. Signaling Network 73, or level 3 is shownbetween the User Part (level 4) and level 2. Level 3 provides theinterface between the User Part and individual link transport. Level 3also manages the SS7 network beyond the individual link level.

[0047]FIG. 4 displays this functionality, and particularly level 3functionality, in greater detail. The functions of Signaling Data Link100 (level 1) and Signaling Link 200 (level 2), Signaling Network 300(level 3), and User Part 400 (level 4) have been discussed above.Signaling Network 300 further includes Signaling Message Handling 310which ensures that messages from User Part 400 are delivered to theproper destination primarily according to a routing label contained inthe message. Signal Message Handling 310 is comprised of Discrimination312, Routing 314, and Distribution 316.

[0048] Prior to a discussion of these elements, a short description ofthe routing label follows. The routing label is contained in eachsignaling message and is used by the relevant User Part to identify thepurpose of the message and is used by level 3 to process and route themessage. The routing label is typically placed at the beginning of thesignaling information field. This routing label contains both aDestination Point Code (DPC) and an Originating Point Code (OPC). Thesepoint codes identify signaling points in the network—and in particular,the originating and destination signaling point for a particularmessage. For example, a message sent from signaling point A to signalingpoint B would have an OPC of A and a DPC of B. A return message wouldreverse the two and have an OPC of B and a DPC of A. The routing labelalso contains a Signaling Link Selection (SLS) field which is used toallow load sharing among links.

[0049] Standard international signaling has a 14 bit DPC, 14 bit OPC,and a 4 bit SLS. Standard U.S. signaling has a 24 bit DPC, 24 bit OPC,and a 5 or 8 bit SLS. The 24 bits of the U.S. point code are broken intothree 8 bit fields that identify the signaling point, the network, andthe network cluster to which the point code belongs. The 8 bit clustermember code 00000000 is reserved for STPs. It should be pointed out thatother signaling conventions are equally applicable to the presentinvention.

[0050] Referring again to FIG. 4, Discrimination 312 analyzes the DPC ofa message to determine if that particular signaling point (performingthe discrimination function) is the destination of the message. If it isnot the destination, the message is directed to Routing 314 for transferon the signaling network. If it is the destination, the message isdirected to Distribution 316 for internal processing.

[0051] Distribution 316 analyzes the service indicator in the message todirect the message to the appropriate user of User Part 400 or to theappropriate part of Signaling Network Management 320.

[0052] Routing 314 accepts messages from Discrimination 312, User Part400 and Signaling Network Management 320. Routing 314 determines thesignaling link over which these outgoing messages are sent and deliversthese messages to level 2 for transmission. Typically, the DPC is usedto select a combined link set and the SLS is used to select the linkwithin the combined link set on which to place the message. The DPCcontrols the actual destination of the message, but many other factorscan affect route choice such as congestion and link failure. SignalingNetwork Management 320 provides this type of information to Routing 314.

[0053] Signaling Network Management 320 is comprised of the followingfunctions: Signaling Link Management 322, Signaling Route Management324, and Signaling Traffic Management 326. The primary function of theseelements is to provide control of the signaling network in the case offailures and congestion.

[0054] Signaling Link Management 322 controls the status of particularlinks. It may use the following procedures to control the links: linkactivation, link deactivation, link restoration, linkset activation, andautomatic allocation.

[0055] Signaling Route Management 324 distributes information about thestatus of the links. This information may indicate failed or congestedlinks and includes: transfer prohibited, transfer allowed, transferrestricted, transfer controlled, signaling route set congestion test,and transfer route set test.

[0056] Signaling Traffic Management 326 is used to re-route signaling inorder to respond to system conditions such as failure or congestion.Signaling can be diverted or partially diverted (inhibited) from onelink to another. These procedures are: changeover, changeback, forcedre-routing, controlled re-routing, MTP restart, management inhibiting,and flow control.

[0057] As those skilled in the art are aware, an STP will house the MTPfunctionality discussed above. In accord with the present invention, thefunctionality of the STP can be altered to provide advantageouscapabilities to a telecommunications system.

[0058]FIG. 5 depicts the functionality of an STP that is in accord withthe present invention. Signaling Data Link 100 (level 1), Signaling Link200 (level 2), Signaling Network 300 (level 3) and User Part 400 (level4) are again shown. Additionally, Discrimination 312, Routing 314,Distribution 316, Signaling Network Management 320 are shown asfunctions of Signaling Network 300. These functions interface asdiscussed above with the following modifications.

[0059] Point Code Conversion 500 is added and shown between level 2 andlevel 3. Point Code Conversion 500 accepts the messages from Level 2 andprovides messages to Discrimination 312. Point Code Conversion 500translates the data in the signaling messages using internal tables.Typically, these tables would logically reside in the MTP softwareprocessed by the STP. The tables would be used to systematically changedesignated DPCs, OPCs, and CICs of the signaling messages directed toDiscrimination 312.

[0060] The appropriate table could be selected based on the linksets orsignaling clusters that the messages arrive on. These linksets andclusters represent the origin of the messages. The tables could also beselected or entered based on the OPC which also represents the origin ofthe messages. The tables could then use the OPC, DPC and/or CIC of themessages to select new data for the conversion, including a new OPC,DPC, and/or CIC. Because Routing 314 will select the outbound link basedon the DPC, Point Code Conversion 500 can change the actual destinationof the signaling message. The tables would be constructed to effectthese desired changes.

[0061] Alternatively, only the DPC could be used for the entireconversion. One table would house DPC to DPC conversions. Additionally,at a point in the STP where processing is still linkset specific (beforelevel 3), MTP linkset processing could place flags in the messages fromdesignated linksets. Those messages coming from the particular linksetswould access the table during subsequent processing when the flag wasdetected, and unflagged messages would not access the table. The tablecould convert combinations of OPC, DPC, and/or CIC into specifiedcombinations of OPC, DPC, and/or CIC.

[0062] Referring again to FIG. 4, it can be shown how Discrimination 312could be altered in accord with the present invention. As discussed,Discrimination 312 determines whether the messages are destined for theSTP itself, a User Part, or another signaling point. A conversion tablewhich is based on linkset, OPC, DPC, and/or CIC could be functionallylocated at this point. The table could process all signaling messages,messages not directed to the STP's DPC, or messages flagged in priorprocessing. The present invention thus applies to a point codeconversion function located at Discrimination 312. The convertedmessages would typically be transferred to Distribution 316 in thiscase.

[0063] In one embodiment, a Digital Switch Corporation model Megahub STPis used. This STP has a particular feature for gateway screening. Thisfeature screens incoming messages with a set of criteria defined foreach linkset delivering messages. The criteria ensures that the messagesare valid for that linkset. At present, this feature only screensmessages and does not convert them or map point codes. In thisembodiment, the Point Code Conversion 500 is located in the STP betweenlevels 2 and 3 at the point of the gateway screening feature.Alternatively, only a flagging function could be placed at the gatewayscreening feature, and a conversion table could convert flagged messagesduring subsequent processing.

[0064] By placing the conversion tables at a point in the STP that isspecific to the incoming linkset, the point code conversions can bespecified for the signaling point(s) transmitting signals on the givenlinkset. In other words, signaling conversions can be specifiedindividually based on the origin of the signaling. This placement alsoallows the level 3 functionality to process the converted signal,instead of processing a signal first, and then converting the pointcodes at the output. Similar advantages can be attained by flagging themessages on particular linksets and using the OPC to ascertain theorigin during subsequent processing.

[0065] User Part 400 (level 4) may include a signaling processor, suchas that described in parent application Ser. No. 08/238,605, entitled“Method, System, and Apparatus for Telecommunications Control”, filed onMay 5, 1994, or in a patent application entitled, “System for ManagingTelecommunications”, filed simultaneously with this application, andassigned to the same assignee. The signaling processor may processparticular ISDN Services User Part (ISUP) signals. In at least oneembodiment, Discrimination 312 would be configured to identify theparticular ISUP messages required by the signaling processor. Thesecriteria could be formed into a table, and the table used to identifythe appropriate ISUP messages from Distribution 312 to transfer to theapplication processor. Like the point code conversion tables, the originof the signaling as represented by the linkset or the OPC could be usedto determine if ISUP should be transferred to the pertinent user part.The OPC, DPC, SLS, CIC and various combinations of these elements couldalso be used for this purpose as well. Those skilled in the art willappreciate other criteria that can be used to route messages to asignaling processor. Additionally, a flagging function could be usedduring linkset specific processing to trigger transfer of ISUP to alevel 4 user during subsequent processing. Those skilled in the art arefamiliar with ISUP identification.

[0066] Another embodiment is shown on FIG. 6 which shows the sameelements as FIG. 5 except for one addition. In this embodiment,additional point code conversion may be required for messages generatedby Signaling Network Management 320 or User Part 400. For theseembodiments, Point Code Conversion 350 is added and shown betweenSignaling Network Management 320 and Routing 314, as well as, betweenUser Part 400 (level 4) and Routing 314. Point Code Conversion 350operates through the use of tables as does Point Code Conversion 500. Inthis way, the point codes in management messages or from a user part canbe converted. Typically, the changes would account for the architecturalchanges in a way similar to Point Code Conversion 500.

[0067] As discussed above, Signaling Network Management 320 is comprisedof three functions: signaling link management, signaling trafficmanagement, and signaling route management. As an example, if asignaling link fails, signaling link management will perceive this andreport it to signaling traffic management which will transmit signals toother signaling points to re-route signaling over an alternate link. Ifthis were to cause congestion on the alternate link, signaling routemanagement would transmit signals to the other signaling pointsinstructing them to restrict use of the congested link.

[0068] Typically, signaling link management messages will not need anypoint code conversion. However, signaling traffic management messagesand signaling route management messages both provide other signalingpoints with signaling instructions for affected signaling links andpoints. Point codes are used to define the affected signaling links andpoints. These messages will need the identification point codes changedto account for new network architectures. These changes are affected bytables as discussed above for the point codes used for routing. Themanagement messages can be specified for each signaling point receivingone of the messages by using the DPC in the routing label to enter thetable. The table would be constructed to give each signaling point whichreceives a management message the point codes it understands in thegiven point code converting scenario.

[0069] Another embodiment is shown in FIG. 7 which depicts atelecommunications system including enhanced STP 600 which operates inaccord with the present invention. STPs 605 and 610 are also shown alongwith switches 615, 620, 625, 630, 635, 640, 645, 650, 655, 660 and 665.STPs 605 and 610 are standard STPs which are known in the art. Theswitches are standard telecommunications switches which are known in theart.

[0070] In FIG. 7, signaling links are represented by the double linesand telecommunications connections are represented by the single lines.The switches and STPs are interconnected with signaling links 700, 705,710, 720, 725, 730, 735, 740, 745, and 750 as shown on the drawing.These links transfer signaling among the switches and STPs as discussedabove. The switches are interconnected by connections 760, 765, 770, 775and 780 as shown on the drawing. The connections carrytelecommunications traffic for users of the telecommunications system asis known in the art.

[0071] To understand this embodiment, it should be pointed out that thesystem architecture has been modified from the following architecture(former connections are not shown): a connection from switch 620 toswitch 650 was re-routed to switch 640, a connection from switch 625 toswitch 655 was re-routed to switch 645, a connection from switch 630 toswitch 660 was re-routed to switch 645, and a connection from switch 635to switch 665 was re-routed to switch 645. The connection from switch615 to switch 650 did not change. The switches have not beenre-programmed to accommodate signaling in accord with the newarchitecture. In addition, STPs 605 and 610 have not been enhanced inaccord with the present invention.

[0072] When switch 630 attempts to connect to switch 660 (its formerconnection), it actually connects to switch 645. However, switch 630would still direct signals to switch 660 when it attempts theconnection. The signaling would be routed to STP 600 and would beprocessed in accord with present invention. The DPC in the signalingwould be converted to represent switch 645 instead of switch 660. Thesignaling would then be routed to switch 645. When switch 645 respondsto switch 630 acknowledging the connection, STP 600 will convert the OPCfrom switch 645 to represent switch 660. In this way, switch 630 is ableto signal and make connections in accord the new architecture withoutbeing re-programmed.

[0073] When switch 620 attempts to connect to switch 650 (its formerconnection), it actually connects to switch 640 over connection 765.However, switch 620 will still attempt to signal switch 650. The signalwould be routed over link 705 through STP 605 and over link 710 to STP600. The DPC would be converted by STP 600 to represent switch 640instead of switch 650. The signal would then be routed to switch 640over link 745. When switch 615 attempts to connect to switch 650 (itsformer and current connection), it will signal switch 650. The signalwould be routed over link 700 through STP 605 and over link 710 to STP600. In this case, no conversion is needed. Thus, sometimes STP 600should convert the DPC for switch 650, and sometimes it should not. Thepresent invention allows STP 600 to discern whether or not to make theconversion.

[0074] STP 600 will identify the source of the signaling before makingthe conversion. This identification could be by OPC. In this way, theconversions for switch 615 would be different than the conversions forswitch 620. For the OPC of switch 615, the DPC for switch 650 would notbe converted. For the OPC of switch 620, the DPC for switch 650 would beconverted to the DPC for switch 640.

[0075] Additionally signaling messages sent in the backward directioncould undergo conversion at the STP in a similar manner. For example,messages from switch 645 to switch 630 and from switch 640 to switch 620would have their OPC converted to represent switch 660 and switch 650respectively. The message from switch 650 to switch 615 would not needthe OPC to be converted.

[0076] Point codes can also be converted at STP 600 based on thesignaling link that the message arrives on. For example, signaling fromswitch 650 to switch 615 does not need conversion, but signaling fromswitch 640 to switch 620 does need convertion to account for the newarchitecture. STP 600 could be configured to convert the OPCs forsignaling messages arriving on signaling link 745 to the OPC for switch650. STP 600 would not convert the OPCs for signaling messages arrivingon signaling link 740. As can be seen, conversion can be based on manyfactors, such as signaling link, OPC, DPC, CIC, SLS, and variouscombinations of these factors. Other factors are also contemplated bythe invention.

[0077] As stated above, signaling networks use management messages tocontrol the signaling network. An example of such messages is a transferrestricted message. If link 750 between STP 600 and switch 645 becomescongested, the signaling route management function in STP 600 wouldgenerate and transmit transfer restricted messages to alleviatecongestion on link 750. In the signals, the congested link is defined bythe point code for switch 645 (the message would still require aseparate OPC and DPC in the routing label for its own routing). However,the other switches in the network would not recognize the point code forswitch 645 because they have not been reprogrammed. As such, they wouldnot recognize the congested link, and might continue to inadvertentlyuse it. STP 600 would convert the point codes in the management messageswhich define the congested link to point codes that would be recognizedand properly acted upon by the signaling points receiving the managementmessages.

[0078] Each signaling point to receive a transfer restricted messagecould get a specific conversion. This is accomplished by using the DPCin the routing label of the management message to identify the receivingsignaling points and obtain the specified conversion. For example, thepoint code defining the congested link might be of switch 655 for themessage sent to switch 625, and it might be of switch 660 for themessage sent to switch 630. In this case the DPCs in the routing labelswould be used to access the specified conversions for the point codedefining the congested link. In some cases conversion may not berequired for certain management message destinations. For example, atransfer restricted message regarding link 740 that is sent to switch615. Message origination recognition could be used to discern whetherconversion is required.

[0079]FIG. 8 depicts another embodiment of the invention. Switch 810 isshown linked to STP 830 and switch 820 is shown linked to STP 840.Signaling processor 850 is shown coupled to STP 830, and signalingprocessor 860 is shown linked to STP 830 and to STP 840. If switch 820sends a message to switch 810 through STP 840, STP 840 could convert theDPC to represent the point code for signaling processor 860. As such,the message would be routed to signaling processor 860. A message fromsignaling processor 860 to switch 820 could have the OPC converted bySTP 840 to represent the OPC of switch 810. In this way switch 820 doesnot need to be re-programmed with the point code for signaling processor860.

[0080] In addition, signaling processor 850 could function as a userpart of STP 830. If switch 810 were to transmit a signal to switch 820,STP 830 could forward the signal to signaling processor 850 instead ofswitch 820. After processing the message, the signaling processor 850could transmit a message to switch 820 and STP 830 could convert the OPCto be that of switch 810. Messages from switch 820 to switch 810 couldbe treated in a similar fashion. In this way, signaling processor 850can process the signaling between the switches in a way that wastransparent to the switches.

[0081] There are many advantages gained from the present invention. Whennetwork architectures change, switches do not need to be re-programmedto signal each other in accord with the new architecture. This avoids acomplex and time consuming task.

[0082] Because the present invention acts on signaling as enters MTPlevel 3 processing, multiple switches can be accommodated. Signalingdirected to any switch in the network which passes through the STP canbe converted. Prior systems only converted signaling after the routefunction of MTP level 3. The present invention allows one integrated andflexible system that acts on MTP level 3 input.

[0083] Because the present invention does not rely on individual trunkidentification, it can efficiently address situations in which entireswitch loads are moved between switches, or when multiple switch loadsare consolidated on a single switch. In these cases, individual trunkrecognition is unnecessary.

[0084] The present invention is capable of selecting destinations forsignaling messages based on the origin of the messages. This allowsconversions to be tailored for each source of signaling. Prior systemsdid not select signaling destinations which corresponded with the originof the message, but based the selection on individual trunkidentification or the destination point code.

[0085] The present invention can also accommodate the introduction ofsignaling processors into a network. Using the STP of the presentinvention, the signaling processors can avoid using point codesaltogether or have a point code that is transparent to the rest of thenetwork.

[0086] The present invention provides an efficient and operational STPwhich can convert signaling to accommodate architectural changesaffecting several switches in a large network. The specification andfigures provide embodiments of the present invention, but the presentinvention is not limited to these specific embodiments. Those skilled inthe art can appreciate many applications of the present invention, whichshould be measured in accord with the following claims.

What is claimed is:
 1. A signaling network, comprising: a signalingtransfer point configured to receive a call-related signaling messagehaving a first point code, convert the first point code to a secondpoint code in the signaling message, transfer the signaling messagehaving the second point code, generate a management message having thesecond point code, convert the second point code to the first point codein the management message, and transfer the management message; and asignaling system configured to receive the management message from thesignaling transfer point.
 2. The signaling network of claim 1, whereinthe signaling message comprises a Signaling System #7 message.
 3. Thesignaling network of claim 1, wherein the signaling transfer point isconfigured to convert the second point code to the first point code inthe management message based on a destination point code of themanagement message.
 4. The signaling network of claim 1, wherein thesignaling transfer point is configured to convert the second point codeto the first point code in the management message based on anorigination point code of the management message.
 5. The signalingnetwork of claim 1, wherein the signaling system comprises a switch. 6.The signaling network of claim 1, wherein the signaling transfer pointis configured to: identify a problem with a link associated with thesecond point code, and convert the second point code to the first pointcode in the management message responsive to identifying the problem. 7.The signaling network of claim 6, wherein the problem with the linkcomprises congestion on the link.
 8. The signaling network of claim 6,wherein the signaling system is configured to: process the managementmessage to avoid transmitting signaling messages to the first pointcode.
 9. The signaling network of claim 1, wherein the signaling systemdoes not recognize the second point code.
 10. The signaling network ofclaim 1, wherein the management message comprises a transfer restrictedmessage.
 11. A method of operating a signaling network, the methodcomprising the steps of: receiving a call-related signaling messagehaving a first point code in a signaling transfer point; and in thesignaling transfer point, converting the first point code to a secondpoint code in the signaling message; transferring the signaling messagehaving the second point code, generating a management message having thesecond point code, converting the second point code to the first pointcode in the management message, and transferring the management message.12. The method of claim 11, wherein the signaling message comprises aSignaling System #7 message.
 13. The method of claim 11, wherein thestep of converting the second point code to the first point code in themanagement message comprises: converting the second point code to thefirst point code in the management message based on a destination pointcode of the management message.
 14. The method of claim 11, wherein thestep of converting the second point code to the first point code in themanagement message comprises: converting the second point code to thefirst point code in the management message based on an origination pointcode of the management message.
 15. The method of claim 11, wherein thesignaling system comprises a switch.
 16. The method of claim 11, furthercomprising the steps of: in the signaling transfer point, identifying aproblem with a link associated with the second point code, andconverting the second point code to the first point code in themanagement message responsive to identifying the problem.
 17. The methodof claim 16, wherein the problem with the link comprises congestion onthe link.
 18. The method of claim 16, further comprising the steps of:receiving the management message in a signaling system, and processingthe management message in the signaling system to avoid transmittingsignaling messages to the first point code.
 19. The method of claim 18,wherein the signaling system does not recognize the second point code.20. The method of claim 11, wherein the management message comprises atransfer restricted message.